Forward Hamzah Ahmed Mahross scored twice while another forward Md Ali Hasan netted one for Yemen.
In the first half of the game, Yemen produced some good chances for dominating Bangladeshi defence but most of their efforts went in vain.
Forwards Ahmed Hasan Musrhed and Md Ali Hasan missed two close-range chances to score for Yemen in a span of only five minutes (13th and 18th minutes).
In the 2nd half, Yemen continued domination with their attacking football and bagged its result in the 64th minute while forward Md Ali Hasan netted the ball with a close range left footer shot from inside the box, utilizing a pass from midfielder Abdulrahman Adel Al-Shami (1-0).
In the 72nd minute, substitute forward Hamzah Ahmed Mahross doubled the margin by a close range header from the goal mouth melee, off a corner from midfielder Md Radhi Ebrahim (2-0).
Just after six minutes, forward Mahross widened the margin netting his 2nd goal of the competition by a low-range left footer shot from the danger zone in the 78th minute, from a pass by another forward Md Ahmed Mahdi (3-0).
Yemen missed another chance to widen the margin in the stoppage time (94th minute) while Bangladesh goalkeeper Md Mehedi Hasan denied the penalty with a fine save from defender Hesham Ahmed Balabl.
Yemeni boys got the penalty when substitute defender Md Ali Shakib roughly tackled forward Md Ahmed Mahdi in the danger zone in the 93rd minute.
The game saw Bangladesh captain Jony Sikder getting yellow card in the 89th minute.
Bangladesh, which put in the Group E of the AFC junior meet along with Qatar, Yemen and Bhutan, started their campaign conceding a 0-2 goals defeat against hosts Qatar in their first match on Thursday night but bounced back in the race crushing Bhutan by 3-0 goals in their second match on Friday.
Bangladesh squad: Md Mehedi Hasan, Apurbo Mali, Sayed Nayeem Ahmed, Jony Sikder, Sajed Hasan Jummon Nijum, Md Rajib Hossain, Al Mirad, Moniul Islam Moin, Sirajul Islam Rana/ Saiful Islam Sumon (83rd), Md Rabiul Alam, Saiful Islam Saeed
Yemen squad: Faisal Md Maroof, Md Naji Al-Qashmi, Hesham Ahmed Balabl, Md Ahmed Mahdi, Hasan Md Al-Kawmani, Ahmed Hasan Musrhed, Abdulrahman Adel Al-Shami, Md Ali Hasan, Ahmed Al-Sowadi, Md Radhi Ebrahim, Ahmed Al-Buraihi.
Referee: Takuto Okabe (Japan)